The aims of this research in this proposal are: (1) Determine optimum methods for producing gamma interferon (gamma IF) in cultured human leucocytes using influenza virus antigens. (2) Characterize the types of interferon induced in lymphocytes from normal individuals and from immunized individuals. (3) Determine the nature of the cross-reactive antigen(s) of the virus which induce high levels of gamma IF in human lymphocytes. (4) Determine if the amount of gamma IF induced correlates with either the antibody level to influenza antigens in the lymphocyte donor, the HLA typing of the lymphocyte donor, or with the viral specific HLA restricted cytotoxic T lymphocyte activity of the cultured lymphocytes. (5) Determine the type and number of lymphocytes which produce gamma IF after stimulation by influenza infected leucocytes. (6) Purify gamma IF from high titered cultures, and use an an antigen to produce polyclonal and monoclonal antibodies to gamma IF. The methods used in this research include separation of human leucocytes obtained from normal and inoculated individuals. The leucocytes will be exposed to purified virus and viral antigens and used to stimulate lymphocytes in culture to induce interferon. Interferon will be assayed using sensitive biological and radioimmunometric techniques. The lymphocytes producing IF will be characterized using cell separation flow centrifugation gradients and the flourescent activated cell sorter. The antigen(s) responsible for IF induction will be analyzed using lymphocytes from immunized individuals, and mice, and by stimulation (in vitro) with purified viral proteins. Polyclonal and monoclonal antibodies to gamma IF will be produced when adequate amounts of purified IF are made available by chromatographic and immunoabsorbent techniques.